// HTMLParser Library $Name: v1_6 $ - A java-based parser for HTML
// http://sourceforge.org/projects/htmlparser
// Copyright (C) 2003 Derrick Oswald
//
// Revision Control Information
//
// $Source: /cvsroot/htmlparser/htmlparser/src/org/htmlparser/filters/HasAttributeFilter.java,v $
// $Author: derrickoswald $
// $Date: 2005/05/15 11:49:04 $
// $Revision: 1.7 $
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//

package org.htmlparser.filters;

import java.util.Locale;

import org.htmlparser.Attribute;
import org.htmlparser.Node;
import org.htmlparser.NodeFilter;
import org.htmlparser.Tag;

/**
 * This class accepts all tags that have a certain attribute, and optionally,
 * with a certain value.
 */
public class HasAttributeFilter implements NodeFilter {
	/**
	 * The attribute to check for.
	 */
	protected String mAttribute;

	/**
	 * The value to check for.
	 */
	protected String mValue;

	/**
	 * Creates a new instance of HasAttributeFilter. With no attribute name,
	 * this would always return <code>false</code> from {@link #accept}.
	 */
	public HasAttributeFilter() {
		this("", null);
	}

	/**
	 * Creates a new instance of HasAttributeFilter that accepts tags with the
	 * given attribute.
	 * 
	 * @param attribute
	 *            The attribute to search for.
	 */
	public HasAttributeFilter(String attribute) {
		this(attribute, null);
	}

	/**
	 * Creates a new instance of HasAttributeFilter that accepts tags with the
	 * given attribute and value.
	 * 
	 * @param attribute
	 *            The attribute to search for.
	 * @param value
	 *            The value that must be matched, or null if any value will
	 *            match.
	 */
	public HasAttributeFilter(String attribute, String value) {
		mAttribute = attribute.toUpperCase(Locale.ENGLISH);
		mValue = value;
	}

	/**
	 * Get the attribute name.
	 * 
	 * @return Returns the name of the attribute that is acceptable.
	 */
	public String getAttributeName() {
		return (mAttribute);
	}

	/**
	 * Set the attribute name.
	 * 
	 * @param name
	 *            The name of the attribute to accept.
	 */
	public void setAttributeName(String name) {
		mAttribute = name;
	}

	/**
	 * Get the attribute value.
	 * 
	 * @return Returns the value of the attribute that is acceptable.
	 */
	public String getAttributeValue() {
		return (mValue);
	}

	/**
	 * Set the attribute value.
	 * 
	 * @param value
	 *            The value of the attribute to accept. If <code>null</code>,
	 *            any tag with the attribute, no matter what it's value is
	 *            acceptable.
	 */
	public void setAttributeValue(String value) {
		mValue = value;
	}

	/**
	 * Accept tags with a certain attribute.
	 * 
	 * @param node
	 *            The node to check.
	 * @return <code>true</code> if the node has the attribute (and value if
	 *         that is being checked too), <code>false</code> otherwise.
	 */
	public boolean accept(Node node) {
		Tag tag;
		Attribute attribute;
		boolean ret;

		ret = false;
		if (node instanceof Tag) {
			tag = (Tag) node;
			attribute = tag.getAttributeEx(mAttribute);
			ret = null != attribute;
			if (ret && (null != mValue))
				ret = mValue.equals(attribute.getValue());
		}

		return (ret);
	}
}
